In recent years, safety has been improved by employing active safety devices, for example, various types of air-bags. More recently, there has been interest for intelligent sensor safety systems for inclusion in automobiles, such intelligent sensor safety systems being operable to sense road conditions external to such automobiles and to apply automatically crash avoidance or crash mitigation measures when potential collision events are identified.
It is envisaged that automobile manufacturer may in the future provide vehicles with forward collision warning (FCW) and forward collision mitigation (FCM) systems. Such FCW and FCM systems may employ microwave radar or lidar sensors to measure distances and velocities of vehicles or similar types of object which could represent crash threats. Moreover, such systems are expected to include computing hardware operable to execute decision algorithms for determining whether or not (or a probability that) a vehicle or object represents a threat and initiate autonomous braking when appropriate. Sensor arrangements such as electro-optical sensors and wide-angle radars in combination with electric power assisted steering (EPAS) and associated data processing systems are capable of potentially providing collision avoidance by autonomous steering intervention. Algorithms for executing decisions regarding steering may also be developed, but these are anticipated to be more complex than corresponding algorithms for executing autonomous braking. Moreover, it is envisaged that a maximum steering force applied in autonomous crash avoidance will not be limited by physical vehicle characteristics but defined by customer requirements or legal regulations.
U.S. Pat. No. 6,873,286 describes a motor vehicle driving aid system. The system comprises detector devices operable to provide electrical signals indicative of a relative distance and relative speed of a motor vehicle with respect to a fixed or moving obstacle ahead thereof. The system further includes a processing and control unit coupled to the detector devices to receive detection signals there from, and also connected to brake actuators for outputting braking instructions thereto. In operation, the processing and control unit is arranged to activate the brake actuators to apply automatic emergency braking to the motor vehicle when the relative distance dR between the motor vehicle and an obstacle present ahead of the vehicle lies between a first predetermined limit value dF and a pre-selected intermediate value dE. The first value dF corresponds to a minimum distance at which it is still possible to avoid a collision by braking.
The distance dE also represents a distance wherein, when less than the value dF, it is no longer possible to avoid a collision event of the motor vehicle only by braking, thus requiring a lateral obstacle avoidance maneuver to be performed. Actuation of an obstacle avoidance maneuver is controlled in the motor vehicle by a steering actuator, for example an electric motor, coupled to a steering column of the vehicle; the steering actuator is controlled from a steering control unit. The control unit is operable to activate an obstacle avoidance function in an event that invoking the function is capable of avoiding a collision event from occurring.
The driving aid system is described as including a frontal microwave radar apparatus for sensing an obstacle in a path of travel of the vehicle. The microwave radar is arranged to perform a scanning function and, in particular, to generate a signal indicative of a relative speed VR and the relative distance dR between the motor vehicle and a potential object ahead thereof. The driving aid system also includes at least one video or electro-optical sensor directed to an area ahead of the motor vehicle, and a series of lateral short-range radar systems and a pair of video or electro-optical sensors for monitoring rear-side areas of the vehicle, these rear-side areas being known as “blind spots”. An option of employing lidar, “laser direction and ranging”, for obstacle detection is also disclosed.
U.S. Pat. No. 7,034,668 describes methods of performing threat assessment of objects for vehicles. The methods involve determining kinematics of the vehicles and of the objects. The methods include computing brake threat numbers (BTNs) and steering threat numbers (STNs). For example, a threat assessment system operable to execute the methods comprises at least one object detection sensor for generating at least one object detection signal, and a controller coupled to the at least one object detection sensor. The controller is operable to compute a braking threat number (BTN) and a steering threat number (STN) in response to processing the at least one object detection signal. Moreover, the controller is operable to determine a threat assessment of the at least one object in response to the braking threat number (BTN) and the steering threat number (STN).
Even though systems for collision course prediction exists in prior art, there still is a need to further improve such systems. Thus, the present invention is concerned with the technical problem of providing advanced steering safety systems which are operable to provide more reliable steering intervention in potential collision situations.